Quint configuration fire apparatus

ABSTRACT

A quint configuration fire apparatus includes a chassis, a body assembly coupled to the chassis and having a storage area configured to receive a ground ladder and a fire hose, a pump coupled to the chassis, a water tank coupled to the chassis, a ladder assembly including a plurality of extensible ladder sections, the ladder assembly having a proximal end that is coupled to the chassis, a single front axle coupled to a front end of the chassis, and a single rear axle coupled to a rear end of the chassis. The center of gravity of at least one of the chassis, the body assembly, the pump, and the water tank are positioned to counterbalance a moment generated by the tip load with the ladder assembly extended to the horizontal reach of at least 90 feet.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This is a continuation of U.S. application Ser. No. 15/351,417, filedNov. 14, 2016, which is a continuation of U.S. application Ser. No.14/552,252, filed Nov. 24, 2014, and is related to U.S. application Ser.No. 15/089,137, filed Apr. 1, 2016, which is a continuation of U.S.application Ser. No. 14/552,240, filed Nov. 24, 2014; U.S. applicationSer. No. 14/552,293, filed Nov. 24, 2014; U.S. application Ser. No.14/552,283, filed Nov. 24, 2014; U.S. application Ser. No. 14/552,260,filed Nov. 24, 2014, now U.S. Pat. No. 9,302,129; and U.S. applicationSer. No. 14/552,275, filed Nov. 24, 2014; all of which are incorporatedherein by reference in their entireties.

BACKGROUND

A quint configuration fire apparatus (e.g., a fire truck, etc.) includesan aerial ladder, a water tank, ground ladders, a water pump, and hosestorage. Aerial ladders may be classified according to their horizontalreach and vertical extension height. Traditionally, weight is added tothe fire apparatus (e.g., by making the various components heavier orlarger, etc.) in order to increase the horizontal reach or verticalextension height of the aerial ladder. Traditional quint configurationfire trucks have included a second rear axle to carry the weightrequired to provide the desired aerial ladder horizontal reach andvertical extension height. Such vehicles can therefore be more heavy,difficult to maneuver, and expensive to manufacture.

SUMMARY

One embodiment relates to a quint configuration fire apparatus. Thequint configuration fire apparatus includes a chassis, a body assemblycoupled to the chassis and having a storage area configured to receive aground ladder and a fire hose, a pump coupled to the chassis, a watertank coupled to the chassis, a ladder assembly including a plurality ofextensible ladder sections, the ladder assembly having a proximal endthat is coupled to the chassis, a single front axle coupled to a frontend of the chassis, and a single rear axle coupled to a rear end of thechassis. The ladder assembly is extensible to provide a horizontal reachof at least 90 feet and a vertical height of at least 95 feet and isconfigured to support a tip load of at least 750 pounds. The center ofgravity of at least one of the chassis, the body assembly, the pump, andthe water tank are positioned to counterbalance a moment generated bythe tip load with the ladder assembly extended to the horizontal reachof at least 90 feet.

Another embodiment relates to a fire apparatus. The fire apparatusincludes, a chassis, a body assembly coupled to the chassis andconfigured to receive a ground ladder, a fire hose, a pump, and a watertank, a ladder assembly including a plurality of extensible laddersections, the ladder assembly having a proximal end that is coupled tothe chassis, a single front axle coupled to the front end of thechassis, and a single rear axle coupled to a rear end of the chassis.The single rear axle includes either a single solid axle configurationextending laterally across the chassis or a first axle having a firstconstant velocity joint and a second axle having a second constantvelocity joint, the first axle and the second axle extending fromopposing lateral sides of a differential. The ladder assembly isextensible to provide a horizontal reach of at least 90 feet and isconfigured to support a tip load of at least 750 pounds. The center ofgravity of at least one of the chassis, the body assembly, the pump, andthe water tank are positioned to counterbalance a moment generated bythe tip load with the ladder assembly extended to the horizontal reachof at least 90 feet.

Another embodiment relates to a quint configuration fire apparatus. Thequint configuration fire apparatus includes a chassis, a body assemblycoupled to the chassis and having a storage area configured to receive aground ladder and a fire hose, a pump coupled to the chassis, a watertank coupled to the chassis, a ladder assembly including a plurality ofextensible ladder sections, the ladder assembly having a proximal endthat is coupled to the chassis, a single front axle coupled to a frontend of the chassis, and a single rear axle coupled to a rear end of thechassis. The single rear axle includes either a single solid axleconfiguration extending laterally across the chassis or a first axlehaving a first constant velocity joint and a second axle having a secondconstant velocity joint, the first axle and the second axle extendingfrom opposing lateral sides of a differential. The ladder assembly isextensible to provide a horizontal reach of at least 90 feet and avertical height of at least 95 feet. The center of gravity of at leastone of the chassis, the body assembly, the pump, and the water tank arepositioned to counterbalance a moment generated by the tip load with theladder assembly extended to the horizontal reach of at least 90 feet.

The invention is capable of other embodiments and of being carried outin various ways. Alternative exemplary embodiments relate to otherfeatures and combinations of features as may be recited herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the followingdetailed description, taken in conjunction with the accompanyingfigures, wherein like reference numerals refer to like elements, inwhich:

FIG. 1 is a front perspective view of a fire apparatus, according to anexemplary embodiment;

FIG. 2 is a rear perspective view of the fire apparatus of FIG. 1,according to an exemplary embodiment;

FIG. 3 is a left side view of the fire apparatus of FIG. 1, according toan exemplary embodiment;

FIG. 4 is a right side view of the fire apparatus of FIG. 1, accordingto an exemplary embodiment;

FIG. 5 is a rear perspective view of a water tank of the fire apparatusof FIG. 1, according to an exemplary embodiment;

FIG. 6 is a front perspective view of various internal components of thefire apparatus of FIG. 1, according to an exemplary embodiment;

FIG. 7 is a front view of the fire apparatus of FIG. 1, according to anexemplary embodiment;

FIG. 8 is a rear view of the fire apparatus of FIG. 1, according to anexemplary embodiment;

FIG. 9 is a top view of the fire apparatus of FIG. 1, according to anexemplary embodiment;

FIG. 10 is a bottom view of the fire apparatus of FIG. 1, according toan exemplary embodiment;

FIG. 11 is a perspective view of a front suspension of the fireapparatus of FIG. 1, according to an exemplary embodiment;

FIG. 12 is a perspective view of a rear suspension of the fire apparatusof FIG. 1, according to an exemplary embodiment;

FIG. 13 is a left side view of a single set of outriggers and astability foot provided with the fire apparatus of FIG. 1, according toan exemplary embodiment;

FIG. 14 is a rear view of the single set of outriggers and the stabilityfoot of FIG. 13 in an extended configuration, according to an exemplaryembodiment;

FIG. 15 is a partial view the single set of outriggers of FIG. 13,according to an exemplary embodiment;

FIG. 16 is a left side view of the fire apparatus of FIG. 1 with anaerial ladder assembly extended, according to an exemplary embodiment;

FIG. 17 is a right side view of the fire apparatus of FIG. 1 with anaerial ladder assembly extended, according to an exemplary embodiment;

FIG. 18 is a top view of the fire apparatus of FIG. 1 with the singleset of outriggers extended and an aerial ladder assembly positionedforward, according to an exemplary embodiment;

FIG. 19 is a top view of the fire apparatus of FIG. 1 with the singleset of outriggers extended and an aerial ladder assembly positioned at aforward angle, according to an exemplary embodiment;

FIG. 20 is a top view of the fire apparatus of FIG. 1 with the singleset of outriggers extended and an aerial ladder assembly positioned toone side, according to an exemplary embodiment; and

FIG. 21 is a top view of the fire apparatus of FIG. 1 with the singleset of outriggers extended and an aerial ladder assembly positioned bothat a rearward angle and backward, according to an exemplary embodiment.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the exemplaryembodiments in detail, it should be understood that the presentapplication is not limited to the details or methodology set forth inthe description or illustrated in the figures. It should also beunderstood that the terminology is for the purpose of description onlyand should not be regarded as limiting.

According to an exemplary embodiment, a quint configuration fireapparatus includes a water tank, an aerial ladder, hose storage, groundladders, a water pump, and a single rear axle. While some traditionalquint configuration fire trucks have a ladder assembly mounted on asingle rear axle chassis, the ladder assembly of such fire truckstraditionally has a vertical extension height of 75-80 feet and 67-72feet of horizontal reach. Vertical extension height may include thedistance from the upper-most rung of the ladder assembly to the groundwhen the ladder assembly is fully extended. Reach may include thehorizontal distance from the point of rotation (e.g., point ofconnection of a ladder assembly to a fire apparatus, etc.) to thefurthest rung when the ladder assembly is extended. Increasing verticalextension height or horizontal reach is traditionally achieved byincreasing the weight of various components (e.g., the aerial ladderassembly, the turntable, etc.). The increased weight, in turn, istraditionally carried by a requisite tandem rear axle. A tandem rearaxle may include two solid axle configurations or may include two pairsof axles (e.g., two pairs of half shafts, etc.) each having a set ofconstant velocity joints and coupling two differentials to two pairs ofhub assemblies. A single rear axle chassis may include one solid axleconfiguration or may include one pair of axles each having a set ofconstant velocity joints and coupling a differential to a pair of hubassemblies, according to various alternative embodiments. According toan exemplary embodiment, the aerial ladder assembly of the quintconfiguration fire apparatus is operable at a vertical extension heightof at least 95 feet (e.g., 105 feet, 107 feet, etc.) and at least 90feet (e.g., at least 100 feet, etc.) of horizontal reach with a tipcapacity of at least 750 pounds. The weight of the chassis and othercomponents is supported by a single rear axle chassis, thereby reducingcost and increasing maneuverability relative to traditional vehicles.

According to the exemplary embodiment shown in FIGS. 1-12, a vehicle,shown as a fire apparatus 10, includes a chassis, shown as a frame 12,that defines a longitudinal axis 14. A body assembly, shown as rearsection 16, axles 18, and a cab assembly, shown as front cabin 20, arecoupled to the frame 12. In one embodiment, the longitudinal axis 14extends along a direction defined by at least one of a first frame rail11 and a second frame rail 13 of the frame 12 (e.g., front-to-back,etc.).

Referring to the exemplary embodiment shown in FIG. 1, the front cabin20 is positioned forward of the rear section 16 (e.g., with respect to aforward direction of travel for the vehicle along the longitudinal axis14, etc.). According to an alternative embodiment, the cab assembly maybe positioned behind the rear section 16 (e.g., with respect to aforward direction of travel for the vehicle along the longitudinal axis14, etc.). The cab assembly may be positioned behind the rear section 16on, by way of example, a rear tiller fire apparatus. In someembodiments, the fire apparatus 10 is a ladder truck with a frontportion that includes the front cabin 20 pivotally coupled to a rearportion that includes the rear section 16.

As shown in FIGS. 2 and 8, the fire apparatus 10 also includes groundladders 46. The ground ladders 46 are stored within compartments thatare closed with doors 30. As shown in FIGS. 2 and 8, the fire apparatus10 includes two storage compartments and doors 30, each to store one ormore individual ground ladders 46. In other embodiments, only onestorage compartment and door 30 is included to store one or more groundladders 46. In still other embodiments, three or more storagecompartments and doors 30 are included to store three or more groundladders 46. As shown in FIGS. 2 and 8, a hose chute 42 is provided oneach lateral side at the rear of the fire apparatus 10. The hose chutes42 define a passageway where one or more hoses may be disposed oncepulled from a hose storage location, shown as hose storage platform 36.The fire apparatus 10 includes additional storage, shown as storagecompartments 32 and 68, to store miscellaneous items and gear used byemergency response personnel (e.g., helmets, axes, oxygen tanks, medicalkits, etc.).

As shown in FIGS. 1 and 7, the fire apparatus 10 includes an engine 60.In one embodiment, the engine 60 is coupled to the frame 12. Accordingto an exemplary embodiment, the engine 60 receives fuel (e.g., gasoline,diesel, etc.) from a fuel tank and combusts the fuel to generatemechanical energy. A transmission receives the mechanical energy andprovides an output to a drive shaft. The rotating drive shaft isreceived by a differential, which conveys the rotational energy of thedrive shaft to a final drive (e.g., wheels, etc.). The final drive thenpropels or moves the fire apparatus 10. According to an exemplaryembodiment, the engine 60 is a compression-ignition internal combustionengine that utilizes diesel fuel. In alternative embodiments, the engine60 is another type of device (e.g., spark-ignition engine, fuel cell,electric motor, etc.) that is otherwise powered (e.g., with gasoline,compressed natural gas, hydrogen, electricity, etc.).

As shown in FIGS. 1-2, the fire apparatus 10 is a quint configurationfire truck that includes a ladder assembly, shown as aerial ladderassembly 200, and a turntable assembly, shown as turntable 300. Theaerial ladder assembly 200 includes a first end 202 (e.g., base end,proximal end, pivot end, etc.) and a second end 204 (e.g., free end,distal end, platform end, implement end, etc.). As shown in FIGS. 1-2,the aerial ladder assembly 200 includes a plurality of ladder sections.In some embodiments, the plurality of sections of the aerial ladderassembly 200 is extendable. An actuator may selectively reconfigure theaerial ladder assembly 200 between an extended configuration and aretracted configuration. By way of example, aerial ladder assembly 200may include a plurality of nesting sections that telescope with respectto one another. In the extended configuration (e.g., deployed position,use position, etc.), the aerial ladder assembly 200 is lengthened, andthe second end 204 is extended away from the first end 202. In theretracted configuration (e.g., storage position, transport position,etc.), the aerial ladder assembly 200 is shortened, and the second end204 is withdrawn towards the first end 202.

According to an exemplary embodiment, the first end 202 of the aerialladder assembly 200 is coupled to the frame 12. By way of example,aerial ladder assembly 200 may be directly coupled to frame 12 orindirectly coupled to frame 12 (e.g., with an intermediatesuperstructure, etc.). As shown in FIGS. 1-2, the first end 202 of theaerial ladder assembly 200 is coupled to the turntable 300. Theturntable 300 may be directly or indirectly coupled to the frame 12(e.g., with an intermediate superstructure, via rear section 16, etc.).As shown in FIG. 1, the turntable 300 includes a railing assembly, shownas hand rails 302, and guard rails, shown as guard rails 304. The handrails 302 provide support for operators aboard the turntable 300. Theguard rails 304 are coupled to the hand rails 302 and provide twoentrances to the turntable 300. An operator may provide a force torotate the guard rails 304 open and gain access to the turntable 300. Inthe embodiment shown in FIG. 2, the turntable 300 rotates relative tothe frame 12 about a generally vertical axis 40. According to anexemplary embodiment, the turntable 300 is rotatable a full 360 degreesrelative to the frame 12. In other embodiments, the rotation of theturntable 300 relative to the frame 12 is limited to a range of lessthan 360 degrees, or the turntable 300 is fixed relative to the frame12. As shown in FIGS. 1-4, the rear section 16 includes a pair ofladders 26 positioned on opposing lateral sides of the fire apparatus10. As shown in FIGS. 1-2, the ladders 26 are coupled to the rearsection 16 with hinges. An operator (e.g., a fire fighter, etc.) mayaccess the turntable 300 by climbing either one of the ladders 26 andentering through the guard rails 304. According to the exemplaryembodiment shown in FIGS. 1-2, the turntable 300 is positioned at therear end of the rear section 16 (e.g., rear mount, etc.). In otherembodiments, the turntable 300 is positioned at the front end of therear section 16, proximate the front cabin 20 (e.g., mid mount, etc.).In still other embodiments, the turntable 300 is disposed along frontcabin 20 (e.g., front mount, etc.).

According to the exemplary embodiment shown in FIGS. 1-2, the first end202 of the aerial ladder assembly 200 is pivotally coupled to theturntable 300. An actuator, shown as cylinder 56, is positioned torotate the aerial ladder assembly 200 about a horizontal axis 44. Theactuator may be a linear actuator, a rotary actuator, or still anothertype of device and may be powered hydraulically, electrically, or stillotherwise powered. In one embodiment, aerial ladder assembly 200 isrotatable between a lowered position (e.g., the position shown in FIG.1, etc.) and a raised position. The aerial ladder assembly 200 may begenerally horizontal or an angle (e.g., 10 degrees, etc.) below thehorizontal when disposed in the lowered position (e.g., a storedposition, etc.). In one embodiment, extension and retraction ofcylinders 56 rotates aerial ladder assembly 200 about the horizontalaxis 44 and raises or lowers, respectively, the second end 204 of aerialladder assembly 200. In the raised position, the aerial ladder assembly200 allows access between the ground and an elevated height for a firefighter or a person being aided by the fire fighter.

According to the exemplary embodiment shown in FIG. 5, a reservoir,shown as water tank 58, is coupled to the frame 12 with asuperstructure. In one embodiment, the water tank 58 is located withinthe rear section 16 and below the hose storage platform 36. As shown inFIG. 5, the water tank 58 is coupled to the frame 12 with a tubularcomponent, shown as torque box 400. In one embodiment, the water tank 58stores at least 500 gallons of water. In other embodiments, thereservoir stores another firefighting agent (e.g., foam, etc.).According to the exemplary embodiment shown in FIGS. 2 and 5, the watertank 58 is filled with a fill dome, shown as fill dome 34.

As shown in FIGS. 1-2, the fire apparatus 10 includes a pump house,shown as pump house 50. A pump 22 may be disposed within the pump house50. By way of example, the pump house 50 may include a pump panel havingan inlet for the entrance of water from an external source (e.g., a firehydrant, etc.). As shown in FIG. 2, an auxiliary inlet, shown as inlet28, is provided at the rear of the fire apparatus 10. The pump house 50may include an outlet configured to engage a hose. The pump 22 may pumpfluid through the hose to extinguish a fire (e.g., water from the inletof the pump house 50, water from the inlet 28, water stored in the watertank 58, etc.).

Referring still to the exemplary embodiment shown in FIGS. 1-2, animplement, shown as nozzle 38 (e.g., deluge gun, water cannon, deck gun,etc.), is disposed at the second end 204 of the aerial ladder assembly200. The nozzle 38 is connected to a water source (e.g., the water tank58, an external source, etc.) via an intermediate conduit extendingalong the aerial ladder assembly 200 (e.g., along the side of the aerialladder assembly 200, beneath the aerial ladder assembly 200, in achannel provided in the aerial ladder assembly 200, etc.). By pivotingthe aerial ladder assembly 200 into the raised position, the nozzle 38may be elevated to expel water from a higher elevation to facilitatesuppressing a fire. In some embodiments, the second end 204 of theaerial ladder assembly 200 includes a basket. The basket may beconfigured to hold at least one of fire fighters and persons being aidedby the fire fighters. The basket provides a platform from which a firefighter may complete various tasks (e.g., operate the nozzle 38, createventilation, overhaul a burned area, perform a rescue operation, etc.).

According to the exemplary embodiment shown in FIGS. 5-6, the torque box400 is coupled to the frame 12. In one embodiment, the torque box 400extends the full width between the lateral outsides of the first framerail 11 and the second frame rail 13 of the frame 12. The torque box 400includes a body portion having a first end 404 and a second end 406. Asshown in FIG. 5, a pedestal, shown as pedestal 402, is attached to thefirst end 404 of the torque box 400. In one embodiment, the pedestal 402is disposed rearward of (i.e., behind, etc.) the single rear axle 18.The pedestal 402 couples the turntable 300 to the torque box 400. Theturntable 300 rotatably couples the first end 202 of the aerial ladderassembly 200 to the pedestal 402 such that the aerial ladder assembly200 is selectively repositionable into a plurality of operatingorientations. According to the exemplary embodiment shown in FIGS. 3-4,a single set of outriggers, shown as outriggers 100, includes a firstoutrigger 110 and a second outrigger 120. As shown in FIGS. 3-4, thefirst outrigger 110 and the second outrigger 120 are attached to thesecond end 406 of the torque box 400 in front of the single rear axle 18and disposed on opposing lateral sides of the fire apparatus 10. Asshown in FIGS. 1-4, the outriggers 100 are moveably coupled to thetorque box 400 and may extend outward, away from the longitudinal axis14, and parallel to a lateral axis 24. According to an exemplaryembodiment, the outriggers 100 extend to a distance of eighteen feet(e.g., measured between the center of a pad of the first outrigger 110and the center of a pad of the second outrigger 120, etc.). In otherembodiments, the outriggers 100 extend to a distance of less than orgreater than eighteen feet. An actuator may be positioned to extendportions of each of the first outrigger 110 and the second outrigger 120towards the ground. The actuator may be a linear actuator, a rotaryactuator, or still another type of device and may be poweredhydraulically, electrically, or still otherwise powered.

According to the exemplary embodiment shown in FIGS. 3-5, a stabilityfoot, shown as stability foot 130, is attached to the first end 404 ofthe torque box 400. An actuator (e.g., a linear actuator, a rotaryactuator, etc.) may be positioned to extend a portion of the stabilityfoot 130 towards the ground. Both the outriggers 100 and the stabilityfoot 130 are used to support the fire apparatus 10 (e.g., whilestationary and in use to fight fires, etc.). According to an exemplaryembodiment, with the outriggers 100 and stability foot 130 extended, thefire apparatus 10 can withstand a tip capacity of at least 750 poundsapplied to the last rung on the second end 204 of the aerial ladderassembly 200 while fully extended (e.g., to provide a horizontal reachof at least 90 feet, to provide a horizontal reach of at least 100 feet,to provide a vertical extension height of at least 95 feet, to provide avertical extension height of at least 105 feet, to provide a verticalextension height of at least 107 feet, etc.). The outriggers 100 and thestability foot 130 are positioned to transfer the loading from theaerial ladder assembly 200 to the ground. For example, a load applied tothe aerial ladder assembly 200 (e.g., a fire fighter at the second end204, a wind load, etc.) may be conveyed into to the turntable 300,through the pedestal 402 and the torque box 400, and into the groundthrough at least one of the outriggers 100 and the stability foot 130.While the fire apparatus 10 is being driven or not in use, the actuatorsof the first outrigger 110, the second outrigger 120, and the stabilityfoot 130 may retract portions of the outriggers 100 and the stabilityfoot 130 into a stored position.

As shown in FIGS. 10 and 12, the single rear axle 18 includes adifferential 62 coupled to a pair of hub assemblies 64 with a pair ofaxle shaft assemblies 52. As shown in FIGS. 10 and 12, the single rearaxle 18 includes a solid axle configuration extending laterally acrossthe frame 12 (e.g., chassis, etc.). A rear suspension, shown as rearsuspension 66, includes a pair of leaf spring systems. The rearsuspension 66 may couple the single solid axle configuration of thesingle rear axle 18 to the frame 12. In one embodiment, the single rearaxle 18 has a gross axle weight rating of no more than (i.e., less thanor equal to, etc.) 33,500 pounds. In other embodiments, a first axleshaft assembly 52 has a first set of constant velocity joints and asecond axle shaft assembly 52 has a second set of constant velocityjoints. The first axle assembly 52 and the second axle assembly 52 mayextend from opposing lateral sides of the differential 62, coupling thedifferential 62 to the pair of hub assemblies 64. As shown in FIGS.10-11, a front suspension, shown as front suspension 54, for the frontaxle 18 includes a pair of independent suspension assemblies. In oneembodiment, the front axle 18 has a gross axle weight rating of no morethan 33,500 pounds.

According to the exemplary embodiment shown in FIGS. 1-12, the aerialladder assembly 200 forms a cantilever structure when at least one ofraised vertically and extended horizontally. The aerial ladder assembly200 is supported by the cylinders 56 and by the turntable 300 at thefirst end 202. The aerial ladder assembly 200 supports static loadingfrom its own weight, the weight of any equipment coupled to the ladder(e.g., the nozzle 38, a water line coupled to the nozzle, a platform,etc.), and the weight of any persons using the ladder. The aerial ladderassembly 200 may also support various dynamic loads (e.g., due to forcesimparted by a fire fighter climbing the aerial ladder assembly 200, windloading, loading due to rotation, elevation, or extension of aerialladder assembly, etc.). Such static and dynamic loads are carried by theaerial ladder assembly 200. The forces carried by the cylinders 56, theturntable 300, and the frame 12 may be proportional (e.g., directlyproportional, etc.) to the length of the aerial ladder assembly 200. Atleast one of the weight of the aerial ladder assembly 200, the weight ofthe turntable 300, the weight of the cylinders 56, and the weight of thetorque box 400 is traditionally increased to increase at least one ofthe extension height rating, the horizontal reach rating, the staticload rating, and the dynamic load rating. Such vehicles traditionallyrequire the use of a chassis having a tandem rear axle. However, theaerial ladder assembly 200 of the fire apparatus 10 has an increasedextension height rating and horizontal reach rating without requiring achassis having a tandem rear axle (e.g., a tandem axle assembly, etc.).According to the exemplary embodiment shown in FIGS. 1-12, the fireapparatus 10 having a single rear axle 18 is lighter, substantially lessdifficult to maneuver, and less expensive to manufacture than a fireapparatus having a tandem rear axle.

According to the exemplary embodiment shown in FIGS. 13-21, the firstoutrigger 110, the second outrigger 120, and the stability foot 130stabilize the fire apparatus 10 when the aerial ladder assembly 200 isin operation (e.g., being used to extinguish a fire with the nozzle 38,extended to rescue pedestrians from a building, etc.). As shown in FIG.13, the first outrigger 110, the second outrigger 120, and the stabilityfoot 130 are disposed a stowed position (e.g., not actuated, notextended, etc.). The first outrigger 110, the second outrigger 120, andthe stability foot 130 may remain in the stowed position while the fireapparatus 10 is being driven, while the fire apparatus 10 is not inoperation (e.g., not being used, parked, etc.), or any other time theaerial ladder assembly 200 is not being utilized during a fire or rescuesituation.

As shown in FIGS. 14-15, the first outrigger 110, the second outrigger120, and the stability foot 130 are disposed in a fully extendedposition. As shown in FIG. 14, the first outrigger 110 includes a firstframe member, shown as first lateral member 112, a first actuator, shownas first cylinder 114, and a first contact pad, shown as first contactpad 118. The first cylinder 114 includes a first cylinder barrel, shownas first cylinder barrel 115, and a first rod, shown as first rod 116.The first rod 116 is coupled to the first contact pad 118. The firstcylinder 114 is positioned to extend the first contact pad 118 downwardby extending the first rod 116 from the first cylinder barrel 115. Thefirst cylinder 114 extends the first contact pad 118 into contact with aground surface, shown as ground surface 170. In one embodiment, thefirst cylinder 114 is a hydraulic cylinder. In other embodiments, thefirst cylinder 114 is another type of actuator (e.g., a linear actuator,a rotary actuator, or still another type of device, etc.) that may bepowered hydraulically, electrically, or still otherwise powered.

As shown in FIGS. 14-15, the second outrigger 120 includes a secondframe member, shown as second lateral member 122, a second actuator,shown as second cylinder 124, and a second contact pad, shown as secondcontact pad 128. The second cylinder 124 includes a second cylinderbarrel, shown as second cylinder barrel 125, and a second rod, shown assecond rod 126. The second rod 126 is coupled to the second contact pad128. The second cylinder 124 is positioned to extend the second contactpad 128 downward by extending the second rod 126 from the secondcylinder barrel 125. The second cylinder 124 extends the second contactpad 128 into contact with the ground surface 170. In one embodiment, thesecond cylinder 124 is a hydraulic cylinder. In other embodiments, thesecond cylinder 124 is another type of actuator (e.g., a linearactuator, a rotary actuator, or still another type of device, etc.) thatmay be powered hydraulically, electrically, or still otherwise powered.

According to the exemplary embodiment shown in FIGS. 6 and 13-14, ahousing, shown as outrigger housing 106, slidably couples the firstoutrigger 110 and the second outrigger 120 to the frame 12. As shown inFIGS. 13-14, the first lateral member 112 and the second lateral member122 are disposed in the fully extended position and spaced a distance160. In one embodiment, an actuator (e.g., a linear actuator, a rotaryactuator, etc.) or a pair of actuators is positioned within theoutrigger housing 106 to extend the first lateral member 112 and thesecond lateral member 122 laterally outward from opposing lateral sidesof the frame 12. The distance 160 may be the distance between the centerof the first contact pad 118 and the center of the second contact pad128 when the pair of outriggers 100 is fully extended. In oneembodiment, the distance 160 is no more than eighteen feet. In otherembodiments, the distance 160 is greater than eighteen feet.

As shown in FIG. 14, the stability foot 130 includes a third actuator,shown as third cylinder 134, and a third contact pad, shown as thirdcontact pad 138. The third cylinder 134 includes a third cylinderbarrel, shown as third cylinder barrel 135, and a third rod, shown asthird rod 136. The third rod 136 is coupled to the third contact pad138. The third cylinder 134 is positioned to extend the third contactpad 138 downward by extending the third rod 136 from the third cylinderbarrel 135. The third cylinder 134 extends the third contact pad 138into contact with the ground surface 170. In one embodiment, the thirdcylinder 134 is a hydraulic cylinder. In other embodiments, the thirdcylinder 134 is another type of actuator (e.g., a linear actuator, arotary actuator, or still another type of device, etc.) that may bepowered hydraulically, electrically, or still otherwise powered.

Referring to FIGS. 13-14, the fire apparatus 10 includes a pair of fronttires, shown as front tires 17, and a set of rear tires, shown as reartires 19. When actuated, the first outrigger 110, the second outrigger120, and the stability foot 130 elevate the rear section 16 of the fireapparatus 10 from the ground surface 170. The front tires 17 may remainin contact with the ground surface 170, while the rear tires 19 may belifted a height, shown as height 150, above the ground surface 170. Inone embodiment, the height 150 is less than twelve inches. In otherembodiments, the height 150 is at least twelve inches.

Referring now to FIGS. 16-17, the aerial ladder assembly 200 of the fireapparatus 10 includes a plurality of extensible ladder sections. Asshown in FIGS. 16-17, the plurality of extensible ladder sectionsincludes a first ladder section, shown as base section 220, a secondladder section, shown as lower middle section 240, a third laddersection, shown as upper middle section 260, and a fourth ladder section,shown as fly section 280. The first end 202 of the aerial ladderassembly 200 may be the proximal end (e.g., base end, pivot end, etc.)of the base section 220. The second end 204 of the aerial ladderassembly 200 may be the distal end (e.g., free end, platform end,implement end, etc.) of the fly section 280. According to an exemplaryembodiment, the second end 204 of the aerial ladder assembly 200 (i.e.,the distal end of the fly section 280, etc.) is extensible to thehorizontal reach of at least 90 feet (e.g., at least 100 feet, etc.)when the aerial ladder assembly 200 is selectively repositioned into aplurality of operating orientations.

As shown in FIGS. 16-21, a load, shown as load 600 (e.g., tip load, tipcapacity, etc.), may be applied to the aerial ladder assembly 200 (e.g.,at the furthest-most rung of fly section 280, etc.), and variouscomponents of the fire apparatus 10 each have a center of gravity(“CG”). Such components may have a first CG, shown as ladder assembly CG610, a second CG, shown as front cabin CG 620, a third CG, shown as pumpCG 630, a fourth CG, shown as water tank CG 640, a fifth CG, shown asrear section CG 650, and a sixth CG, shown as turntable CG 660. Theladder assembly CG 610 may be representative of the CG of the fourladder sections of the aerial ladder assembly 200 (e.g., the basesection 220, the lower middle section 240, the upper middle section 260,the fly section 280, etc.). The front cabin CG 620 may be representativeof the CG of the various components in and around the front cabin 20(e.g., the front axle 18, front tires 17, front suspension 54, frontbody assembly, front portion of the chassis, etc.). The pump CG 630 maybe representative of the CG of the pump 22 and the components of thepump house 50. The water tank CG 640 may be representative of the CG ofthe water tank 58. The rear section CG 650 may be representative of theCG of the various component of the rear section 16 (e.g., the rear axle18, rear tires 19, outriggers 100, stability foot 130, torque box 400,pedestal 402, ground ladders 46, rear body assembly, rear portion of thechassis, etc.). The turntable CG 660 may be representative of the CG ofthe turntable 300.

As shown in FIGS. 18-21, the aerial ladder assembly 200 is disposed in aretracted configuration. During operation, the aerial ladder assembly200 may be extended as shown in FIGS. 16-17. While shown in FIGS. 18-21as disposed in the retracted configuration, it should be understood thatthe aerial ladder assembly 200 may be extended during use in variousoperating orientations. A variety of stability lines are generated forthe fire apparatus 10 while in the various operating orientations. Thestability lines may be disposed along the single front axle 18, throughthe center of the single front axle 18 and one of the first outrigger110 and the second outrigger 120, through the stability foot 130 and oneof the first outrigger 110 and the second outrigger 120, or laterallyacross the stability foot 130, among other alternatives.

The various components of the fire apparatus 10 produce a positivemoment or a negative moment that varies based on the location of theirrespective CGs. Positive moments (e.g., torques, etc.) may be generatedby load 600 and the weights of components having CGs located on a firstside of the stability line (e.g., a side of the stability line where theload 600 is located, etc.). Negative moments may be generated by theweights of components having CGs located on an opposing second side ofthe stability line (e.g., a side of the stability line where the load600 is not located, etc.). According to an exemplary embodiment, variouscomponents of the fire apparatus 10 (e.g., frame 12, turntable 300, rearsection 16, pump 22, water tank 58, etc.) are positioned such that theirweights counterbalance a total positive moment (e.g., generated by load600 and the weights of components having CGs located on the first sideof the stability line, etc.) when the aerial ladder assembly 200 isextended to the horizontal reach of at least 90 feet (e.g., at least 100feet, etc.). The magnitude of the positive and negative moments areproportional to the distances (e.g., perpendicular distances, etc.)between the component's CG and the stability line (e.g., a greaterdistance from the stability line increases the moment, a shorterdistance from the stability line decreases the moment, a CG disposed onthe stability line results in a negligible moment or zero moment, etc.).

As shown in FIGS. 16-18, the aerial ladder assembly 200 is configured ina first operating orientation. In the first operating orientation, theaerial ladder assembly 200 is disposed in a forward position in whichthe aerial ladder assembly 200 extends over the front cabin 20 (e.g.,parallel to the longitudinal axis 14, etc.). When aerial ladder assembly200 is extended, the ladder assembly CG 610 may be positioned forward ofthe front cabin 20 (e.g., within the lower middle section 240, near theconnection between the lower middle section 240 and the upper middlesection 260 of the aerial ladder assembly 200, etc.). As shown in FIG.18, the fire apparatus 10 includes a stability line 500 when the aerialladder assembly 200 is selectively positioned in the first operatingorientation (e.g., a forward position, etc.). The stability line 500 isdisposed along the single front axle 18. As shown in FIG. 18, when theload 600 is applied to the second end 204 of the aerial ladder assembly200 while in the first operating orientation, the load 600 generates afirst positive moment 502 about the stability line 500. The ladderassembly CG 610 generates a second positive moment 502 about thestability line 500. The front cabin CG 620 may generate a negligiblemoment about the stability line 500 as the front cabin CG 620 may besubstantially disposed along the stability line 500. The pump CG 630,the water tank CG 640, the rear section CG 650, and the turntable CG660, among other components, generate negative moments 504 about thestability line 500. In the first operating orientation, the negativemoments 504 at least balance the positive moments 502 while the aerialladder assembly 200 is extended to the horizontal reach of at least 90feet (e.g., at least 100 feet, etc.) and a load 600 of at least 750pounds is applied.

As shown in FIG. 19, the aerial ladder assembly 200 is configured in asecond operating orientation. In the second operating orientation, theaerial ladder assembly 200 is disposed in a forward angled position inwhich the aerial ladder assembly 200 extends off to a side of the fireapparatus 10, biased towards the front cabin 20. As shown in FIG. 19,the fire apparatus 10 includes a stability line 510 when the aerialladder assembly 200 is selectively positioned in the forward angledposition (e.g., a forward angled position to the right side, a forwardangled position to the left side, etc.). As shown in FIG. 19, the aerialladder assembly 200 is selectively positioned to extend off to the rightside of the fire apparatus 10 at a forward angle. The stability line 510may extend through the center of the single front axle 18 and the secondoutrigger 120. In other embodiments, the aerial ladder assembly 200 isselectively positioned to extend off to the left side of the fireapparatus 10 at a forward angle, and the stability line 510 may extendthrough the center of the single front axle 18 and the first outrigger110. As shown in FIG. 19, when the load 600 is applied to the second end204 of the aerial ladder assembly 200 while in the second operatingorientation, the load 600 generates a first positive moment 512 aboutthe stability line 510. The ladder assembly CG 610 generates a secondpositive moment 512 about the stability line 510. The front cabin CG 620may generate a negligible moment about the stability line 510 as thefront cabin CG 620 may be substantially disposed along the stabilityline 510. The pump CG 630, the water tank CG 640, the rear section CG650, and the turntable CG 660, among other components, generate negativemoments 514 about the stability line 510. In the second operatingorientation, the negative moments 514 at least balance the positivemoments 512 while the aerial ladder assembly 200 is extended to thehorizontal reach of at least 90 feet (e.g., at least 100 feet, etc.) anda load 600 of at least 750 pounds is applied.

As shown in FIG. 20, the aerial ladder assembly 200 is configured in athird operating orientation. In the third operating orientation, theaerial ladder assembly 200 is disposed in a sideward position in whichthe aerial ladder assembly 200 extends from a lateral side of thechassis (e.g., perpendicular to the longitudinal axis 14, etc.). Asshown in FIG. 19, the fire apparatus 10 includes a stability line 520when the aerial ladder assembly 200 is selectively positioned in thethird operating orientation (e.g., laterally to the right side,laterally to the left side, etc.). As shown in FIG. 19, the aerialladder assembly 200 is selectively positioned to extend laterally off tothe right side of the fire apparatus 10. The stability line 520 mayextend through the center of the single front axle 18 and the secondoutrigger 120. In other embodiments, the aerial ladder assembly isselectively positioned to extend laterally off to the left side of thefire apparatus 10, and the stability line 520 may extend through thecenter of the single front axle 18 and the first outrigger 110. As shownin FIG. 20, when the load 600 is applied to the second end 204 of theaerial ladder assembly 200 while in the third operating orientation, theload 600 generates a first positive moment 522 about the stability line520. The ladder assembly CG 610 generates a second positive moment 522about the stability line 520. The front cabin CG 620 may generate anegligible moment about the stability line 520 as the front cabin CG 620may be substantially disposed along the stability line 520. The pump CG630, the water tank CG 640, the rear section CG 650, and the turntableCG 660, among other components, generate negative moments 524 about thestability line 520. In the third operating orientation, the negativemoments 524 at least balance the positive moments 522 while the aerialladder assembly 200 is extended to the horizontal reach of at least 90feet (e.g., at least 100 feet, etc.) and a load 600 of at least 750pounds is applied.

As shown in FIG. 21, the aerial ladder assembly 200 is configured in afourth operating orientation and a fifth operating orientation. In thefourth operating orientation, the aerial ladder assembly 200 is disposedin a rearward angled position in which the aerial ladder assembly 200 isextended off to a side of the fire apparatus 10, biased towards the rearsection 16. As shown in FIG. 21, the fire apparatus 10 includes astability line 530 when the aerial ladder assembly 200 is selectivelypositioned in the fourth operating orientation (e.g., a rearward angledposition to the right side, a rearward angled position to the left side,etc.). As shown in FIG. 21, the aerial ladder assembly 200 isselectively positioned to extend off to the right side of the fireapparatus 10 at a rearward angle. The stability line 530 extends throughthe second outrigger 120 and the stability foot 130. In otherembodiments, the aerial ladder assembly 200 is selectively positioned toextend off to the left side of the fire apparatus 10 at a rearwardangle, and the stability line 530 extends through the first outrigger110 and the stability foot 130. As shown in FIG. 21, the load 600 isapplied to the second end 204 of the aerial ladder assembly 200 while inthe fourth operating orientation, and the load 600 generates a firstpositive moment 532 about the stability line 530. The ladder assembly CG610 generates a second positive moment 532 about the stability line 530.The front cabin CG 620, the pump CG 630, the water tank CG 640, the rearsection CG 650, and the turntable CG 660, among other components,generate negative moments 534 about the stability line 530. In thefourth operating orientation, the negative moments 534 at least balancethe positive moments 532 while the aerial ladder assembly 200 isextended to the horizontal reach of at least 90 feet (e.g., at least 100feet, etc.) and a load 600 of at least 750 pounds is applied.

FIG. 21 also shows the aerial ladder assembly 200 configured in a fifthoperating orientation. In the fifth operating orientation, the aerialladder assembly 200 is disposed in a rearward position in which theaerial ladder assembly 200 extends away from the front cabin 20 (e.g.,parallel to the longitudinal axis 14, opposite of the first operatingorientation, etc.). As shown in FIG. 21, the fire apparatus 10 includesa stability line 540 when the aerial ladder assembly 200 is selectivelypositioned in the fifth operating orientation (e.g., an opposingrearward position, etc.). The stability line 540 is a line disposedlaterally across the stability foot 130 (e.g., perpendicular to theaerial ladder assembly 200, perpendicular to the longitudinal axis 14,etc.). As shown in FIG. 21, when the load 600 is applied to the secondend 204 of the aerial ladder assembly 200 while in the fifth operatingorientation, the load 600 generates a first positive moment 542 aboutthe stability line 540. The ladder assembly CG 610 generates a secondpositive moment 542 about the stability line 500. The front cabin CG620, the pump CG 630, the water tank CG 640, the rear section CG 650,and the turntable CG 660, among other components, generate negativemoments 544 about the stability line 540. In the fifth operatingorientation, the negative moments 544 at least balance the positivemoments 542 while the aerial ladder assembly 200 is extended to thehorizontal reach of at least 90 feet (e.g., at least 100 feet, etc.) anda load 600 of at least 750 pounds is applied.

It is important to note that the construction and arrangement of theelements of the systems and methods as shown in the exemplaryembodiments are illustrative only. Although only a few embodiments ofthe present disclosure have been described in detail, those skilled inthe art who review this disclosure will readily appreciate that manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements. It should be noted that the elements and/or assemblies ofthe components described herein may be constructed from any of a widevariety of materials that provide sufficient strength or durability, inany of a wide variety of colors, textures, and combinations.Accordingly, all such modifications are intended to be included withinthe scope of the present inventions. Other substitutions, modifications,changes, and omissions may be made in the design, operating conditions,and arrangement of the preferred and other exemplary embodiments withoutdeparting from scope of the present disclosure or from the spirit of theappended claims.

What is claimed is:
 1. A quint configuration fire apparatus, comprising:a chassis; a body assembly coupled to the chassis and having a storagearea configured to receive a ground ladder and a fire hose; a pumpcoupled to the chassis; a water tank coupled to the chassis; a ladderassembly including a plurality of extensible ladder sections, the ladderassembly having a proximal end that is coupled to the chassis; a singlefront axle coupled to a front end of the chassis; and a single rear axlecoupled to a rear end of the chassis, wherein the ladder assembly isextensible to provide a horizontal reach of at least 90 feet and avertical height of at least 95 feet, wherein the ladder assembly isconfigured to support a tip load of at least 750 pounds, and wherein thecenter of gravity of at least one of the chassis, the body assembly, thepump, and the water tank are positioned to counterbalance a momentgenerated by the tip load with the ladder assembly extended to thehorizontal reach of at least 90 feet.
 2. The fire apparatus of claim 1,further comprising a pedestal coupling the ladder assembly to thechassis and defining an axis about which the ladder assembly isconfigured to rotate.
 3. The fire apparatus of claim 2, furthercomprising a turntable rotatably coupling the proximal end of the ladderassembly to the pedestal such that the ladder assembly is selectivelyrepositionable into a plurality of operating orientations, wherein thehorizontal reach is defined between the axis about which the ladderassembly is configured to rotate and a distal end of the ladderassembly, and wherein the vertical height is defined between a distalrung of the ladder assembly and a ground surface.
 4. The fire apparatusof claim 3, further comprising a cab assembly coupled to the front endof the chassis, wherein the plurality of operating orientations includesa forward position in which the ladder assembly extends over the cabassembly, a rearward position in which the ladder assembly extends awayfrom the cab assembly, and a sideward position in which the ladderassembly extends from a lateral side of the chassis.
 5. The fireapparatus of claim 4, wherein the plurality of extensible laddersections includes a first ladder section, a second ladder section, athird ladder section, and a fourth ladder section, wherein the distalend of the ladder assembly is extensible to the horizontal reach of atleast 90 feet when the ladder assembly is oriented in the sidewardposition.
 6. The fire apparatus of claim 1, further comprising a pair ofoutriggers coupled to the chassis and moveable between a fully extendedposition and a retracted position, wherein the pair of outriggersprotrude from opposing lateral sides of the chassis when in the fullyextended position.
 7. The fire apparatus of claim 6, wherein a pair ofcontact pads associated with the pair of outriggers are spaced adistance of no more than 18 feet when the pair of outriggers are in thefully extended position.
 8. The fire apparatus of claim 7, wherein thesingle rear axle has a gross axle weight rating of no more than 33,500pounds.
 9. The fire apparatus of claim 8, further comprising at leastone of a leaf spring suspension system and an air suspension systemcoupling the single solid axle configuration to the chassis.
 10. Thefire apparatus of claim 8, further comprising a first independentsuspension assembly coupled to the first axle and a second independentsuspension assembly coupled to the second axle.
 11. A fire apparatus,comprising: a chassis; a body assembly coupled to the chassis andconfigured to receive a ground ladder, a fire hose, a pump, and a watertank; a ladder assembly including a plurality of extensible laddersections, the ladder assembly having a proximal end that is coupled tothe chassis; a single front axle coupled to a front end of the chassis;and a single rear axle coupled to a rear end of the chassis, wherein thesingle rear axle comprises either: a single solid axle configurationextending laterally across the chassis, or a first axle having a firstconstant velocity joint and a second axle having a second constantvelocity joint, the first axle and the second axle extending fromopposing lateral sides of a differential; wherein the ladder assembly isextensible to provide a horizontal reach of at least 90 feet, whereinthe ladder assembly is configured to support a tip load of at least 750pounds, and wherein the center of gravity of at least one of thechassis, the body assembly, the pump, and the water tank are positionedto counterbalance a moment generated by the tip load with the ladderassembly extended to the horizontal reach of at least 90 feet.
 12. Thefire apparatus of claim 11, further comprising a pedestal coupling theladder assembly to the chassis and defining an axis about which theladder assembly is configured to rotate.
 13. The fire apparatus of claim12, further comprising a turntable rotatably coupling the proximal endof the ladder assembly to the pedestal such that the ladder assembly isselectively repositionable into a plurality of operating orientations,wherein the horizontal reach is defined between the axis about which theladder assembly is configured to rotate and a distal end of the ladderassembly.
 14. The fire apparatus of claim 13, further comprising a cabassembly coupled to the front end of the chassis, wherein the pluralityof operating orientations includes a forward position in which theladder assembly extends over the cab assembly, a rearward position inwhich the ladder assembly extends away from the cab assembly, and asideward position in which the ladder assembly extends from a lateralside of the chassis.
 15. The fire apparatus of claim 14, wherein theplurality of extensible ladder sections includes a first ladder section,a second ladder section, a third ladder section, and a fourth laddersection, wherein the distal end of the ladder assembly is extensible tothe horizontal reach of at least 90 feet when the ladder assembly isoriented in the sideward position.
 16. The fire apparatus of claim 11,further comprising a pair of outriggers coupled to the chassis andmoveable between a fully extended position and a retracted position,wherein the pair of outriggers protrude from opposing lateral sides ofthe chassis when in the fully extended position.
 17. The fire apparatusof claim 16, wherein a pair of contact pads associated with the pair ofoutriggers are spaced a distance of no more than 18 feet when the pairof outriggers are in the fully extended position.
 18. The fire apparatusof claim 17, wherein the single rear axle has a gross axle weight ratingof no more than 33,500 pounds.
 19. The fire apparatus of claim 18,further comprising either: at least one of a leaf spring suspensionsystem and an air suspension system coupling the single solid axleconfiguration to the chassis, or a first independent suspension assemblycoupled to the first axle and a second independent suspension assemblycoupled to the second axle.
 20. A quint configuration fire apparatus,comprising: a chassis; a body assembly coupled to the chassis and havinga storage area configured to receive a ground ladder and a fire hose; apump coupled to the chassis; a water tank coupled to the chassis; aladder assembly including a plurality of extensible ladder sections, theladder assembly having a proximal end that is coupled to the chassis; asingle front axle coupled to a front end of the chassis; and a singlerear axle coupled to a rear end of the chassis, wherein the single rearaxle comprises either: a single solid axle configuration extendinglaterally across the chassis, or a first axle having a first constantvelocity joint and a second axle having a second constant velocityjoint, the first axle and the second axle extending from opposinglateral sides of a differential; wherein the ladder assembly isextensible to provide a horizontal reach of at least 90 feet and avertical height of at least 95 feet, and wherein the center of gravityof at least one of the chassis, the body assembly, the pump, and thewater tank are positioned to counterbalance a moment generated by thetip load with the ladder assembly extended to the horizontal reach of atleast 90 feet.